Color photographic light-sensitive materials using various "diffusible dye"-releasing compounds (dye releasers) are known. Typical examples of these diffusible dye-releasing compounds include: p-sulfonamidonaphthol dye releasers, as described, for example, in U.S. Pat. Nos. 3,928,312, 4,076,529, 4,152,153, 4,135,929 and 4,258,120 and Published Application No. B351,673; o-sulfonamidonaphthol dye releasers as described in U.S. Pat. No. 4,053,312; o-sulfonamidophenol dye releasers as described in U.S. Pat. No. 4,055,428, Japanese Patent Application (OPI) Nos. 16130/81, 16131/81 and 12642/81 (the term "OPI" as used herein means an "unexamined published Japanese patent application"); heterocyclic dye releasers as described in U.S. Pat. Nos. 4,179,291 and 4,273,855; and dye releasers as described in U.S. Pat. No. 4,110,113 and West German Pagent Application (OLS) No. 2,534,424. Processes for forming color diffusion transfer image using these compounds as mentioned above are also disclosed in the above-described literature in detail. These compounds are generally referred to as dye-releasing redox (DRR) compounds and are compounds comprising a group referred to as a "redox mother nucleus" and a dye (including a dye precursor) portion linked to the group. Upon exposing the dye-releasing redox compounds in admixture with a light-sensitive silver halide emulsion, and then developing, the redox mother nuclei are oxidized or reduced depending on the amount of silver halide developed. In certain redox compounds, the oxidized product is decomposed into a dye portion containing a diffusible sulfonamido group and a non-diffusible quinone or similar member under attack of an alkaline processing solution. The thus-formed diffusible dye is transferred to an image-receiving layer.
Typical examples of reduction-type redox compounds which release a dye upon reduction are those utilizing an intramolecular nucleophilic reaction.
Examples of redox compounds releasing a cyan dye are described, for example, in Japanese Patent Application (OPI) Nos. 126331/74, 109928/76, 143323/78 and 99431/79. The cyan dye-releasing redox compounds described in the literature, however, have several technical problems; for example, the density of transferred images is insufficient, the transfer speed of the dye portion is low, the stability of the transferred dyes is poor (for example, light-fastness is poor and the discoloration of color images with exposure to light is large), and the density of transferred images considerably changes depending on the processing temperature. Among known compounds, compounds as described in Japanese Patent Application (OPI) No. 99431/79 are relatively good, but are not sufficiently satisfactory.